1. Field of the Invention
The present invention relates to an image display method. More particularly, the present invention relates to an image display method for displaying a digest of a moving image.
2. Description of the Background Art
When the contents of a plurality of moving images stored in a video recording medium are checked, it is effective to display a content list (a digest screen) of thumbnail images of the moving images by sequentially reading the stored moving image data.
As one example of the video recording medium, an optical disk will be described.
FIG. 13 is a flowchart for describing a conventional image display method. In FIG. 13, a table stored in a predetermined location on an optical disk is read, and addresses (minute, second, frame) of all moving image data stored in the optical disk are obtained (S1301). Next, a start address of moving image data to be displayed is extracted (S1302), data is read from the optical disk by moving an optical head to a location of the extracted start address (S1303), and the read data is input to an MPEG decoder (S1304). When a frame of an MPEG image is detected in data following the start address, a size of the image data of the frame is reduced (S1305), and a display device is caused to display the resultant thumbnail image (S1306). Such an operation is repeated a predetermined times (e.g., as many as the number of images which can be displayed on the display device) (S1307).
Also, there is a method of detecting audio data and displaying an I picture when a predetermined time period has elapsed after detection of the audio data (Japanese Patent Gazette No. 3110376).
In the above-described conventional image display method, a thumbnail image of an image detected first in data following the start address is displayed. As a result, in the case where a moving image whose screen gradually fades in (as shown in FIG. 14, for example) is included in a video recording medium, a thumbnail image generated from such a moving image is a black image like a thumbnail image 151 shown in FIG. 15. As such, the problem with the above-described conventional image display method is that a user cannot grasp the contents of such a moving image.
Also, there may be a method of detecting brightness of an image for displaying a thumbnail image of a frame when an image whose brightness is equal to or greater than a predetermined level is input. However, a thumbnail image of a moving image which starts from a white (bright) image is plain white, and its content is impossible to understand. As such, a problem with the above-described method is that the user cannot grasp the contents of such a moving image.
Also, by the method of detecting audio data and displaying an I picture when a predetermined time period has elapsed after detection of the audio data, a first image may not be displayed even if the first image of the moving image is a significant image to be displayed. Also, in the case where a video recording medium includes a moving image on which audio data is not multiplexed, a digest (a thumbnail image) of such a moving image is not displayed, which is also a problem.
Therefore, an object of the present invention is to provide an image display method, an image display program, and an image display apparatus capable of displaying a significant thumbnail image by which a user can grasp the contents thereof when a digest of a moving image is displayed.